Wireless Technologies Wireless has become the platform for many applications with direct impact on virtually every aspect of life, evolving well beyond mobile phones and PDAs to other devices, services, channels, and content. Microwave circuits afford a wider frequency spectrum and extremely short antennae. With GaAs and SiGe, entire microwave transceivers can be inexpensively put on a single chip. Modulation methods like spread-spectrum and orthogonal frequency-division multiplexing bring greater spectral efficiency and more bits/Hz of bandwidth, and lead to less susceptibility to noise, interference, and multi-path distortion. On-chip DSPs allow new signal-processing functions. RFID chips are providing improvements in warehousing, materials handling, and shipping operations, replacing bar-code labels in many applications.